MTN doesn’t update Bureau Details

I went into arrears on a Cell phone contract I had with MTN and was handed over to SAYA recoveries,I paid up the balance and everything I owe MTN through their collections company and they gave me a paid up letter however on my credit score rating it shows I still owe MTN and it recently lowered my credit score by a further 22 points again this month but I paid up this account in April 2020 , I’ve been to numerous MTN stores but they’re not able to help,when I call Saya recoveries they say MTN needs to update it , I have escalated this matter with MTN in Gateway Mall in Durban since May 2020 till this day it has not been fixed,please help me fix this as I am not able to take any credit cause of this debt I’ve already paid!!!